Capture of gases emitted from power plants is an area of increasing interest. Power plants based on the combustion of petroleum products generate carbon dioxide as a by-product. Historically this carbon dioxide has been released into the atmosphere after combustion. However, it is becoming increasingly desirable to capture the carbon dioxide generated by power plants and put it to alternative uses. Indeed, the demand for simultaneous power and natural gas, hydrocarbons and valuable industrial chemicals for consumer products is becoming increasingly insatiable.
For example, existing natural and industrial sources of inert gases cannot meet the growing worldwide demand, especially of CO2 and N2, for Enhanced Oil Recovery (EOR) and Enhanced Gas Recovery (EGR). Simultaneously it is becoming imperative to capture and sequester greenhouse gases such as CO2 from power generation plants.
Where available, natural sources of CO2 are produced and distributed in a pipeline network that provides the CO2 to oil fields where CO2 EOR tertiary recovery method will extend the production lifetime of the oil field. However, this type of naturally sourced CO2 and associated pipeline infrastructure only exists in the US, specifically in the Permeian Basin and in the southeast, Gulf Coast region of the US. In other major oil producing areas, such as the Middle East, neither naturally sourced CO2 nor a CO2 pipeline network exists. Furthermore, the USGS has published analyses that conclude that the demand for CO2 for CO2 EOR exceeds the available supply of naturally sourced CO2. Therefore, new technology is required for generating CO2 at low cost. Furthermore, when combined with the emergent need to reduce the emission of CO2 from power plants, the new technology should enable the capture of CO2 from power plants at low cost. Ideally, the technology that would enable the low cost capture of CO2 for EOR would also provide N2 for EGR or EOR at a cost which is lower than that which is currently possible using current technology (which is N2 generated using a cryogenic air separation plant.)
The invention described herein enables the simultaneous economic production of multiple products to meet the demands described above, i.e., CO2, N2 and electric power production and hydrocarbons. These products can be generated by the integration of adsorption (PSA) separations processes with an advanced power generation system and hydrocarbon reservoirs. One example of such an advanced generation system is the advanced combined cycle turbine system, known as ULET (Ultra Low Emissions Turbine).
Combined cycle power plants provide an efficient way to generate electricity from the burning of petroleum products or other carbon-based fuels. Combined cycle power plants can leverage an initial combustion reaction to power multiple turbines for generation of electricity, leading to more efficient power generation. However, conventional methods for capturing CO2 and N2 tend to reduce the efficiency of electricity generation, due to the additional energy required.
U.S. Published Patent Application No. 2013/0333391 describes methods for capturing CO2 emissions utilizing single-stage pressure swing adsorption. That application teaches passing a portion of recycled exhaust gas into a swing adsorption reactor with an adsorbent material, recovering an N2 stream from a forward end of the reactor, reducing the pressure in the swing adsorption reactor, and purging the swing adsorption reactor with a steam purge to generate a CO2 recovery stream.
Other potentially relevant publications can include: U.S. Patent Application Publication No. 20120318533, European Patent Application No. EP 2220338, an article by Reijers et al., Ind. Eng. Chem. Res., 2009, 48, 6966, and an article by Wright et al., Energy Procedia, 2011, 4, 1457, inter alia. Each of the foregoing references is hereby incorporated by reference.